Add MCP client configuration examples to CONTRIBUTING.md (#508)

* docs: restore full MCP client JSON configs to CONTRIBUTING.md

Reinstate the copy-pasteable JSON configurations for running all examples
with MCP clients (npx-based and local development), which were removed
from README.md in 2af02ba. Placed in CONTRIBUTING.md as a better home
for contributor-facing setup instructions.

https://claude.ai/code/session_014pjt7bE4ckHns5QFPkdWQp

* Use start:stdio in local dev config, add missing scripts to 9 examples

Update the local development JSON config in CONTRIBUTING.md to use
`npm --silent run start:stdio` instead of manual bash commands.

Add `serve:stdio` and `start:stdio` scripts to the 9 examples that
were missing them (basic-server-*, sheet-music, transcript,
video-resource, debug) to match the pattern already in place for the
other 11 showcase examples.

https://claude.ai/code/session_014pjt7bE4ckHns5QFPkdWQp

* style: auto-fix prettier formatting

---------

Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

examples/basic-server-react/package.json

@@ -27,7 +27,9 @@
     "build": "tsc --noEmit && cross-env INPUT=mcp-app.html vite build && tsc -p tsconfig.server.json && bun build server.ts --outdir dist --target node && bun build main.ts --outfile dist/index.js --target node --external \"./server.js\" --banner \"#!/usr/bin/env node\"",
     "watch": "cross-env INPUT=mcp-app.html vite build --watch",
     "serve": "bun --watch main.ts",
+    "serve:stdio": "bun main.ts --stdio",
     "start": "cross-env NODE_ENV=development npm run build && npm run serve",
+    "start:stdio": "cross-env NODE_ENV=development npm run build 1>&2 && npm run serve:stdio",
     "dev": "cross-env NODE_ENV=development concurrently \"npm run watch\" \"npm run serve\"",
     "prepublishOnly": "npm run build"
   },